CVE-2022-49605

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

igc: Reinstate IGC_REMOVED logic and implement it properly

The initially merged version of the igc driver code (via commit

146740f9abc4, "igc: Add support for PF") contained the following

IGC_REMOVED checks in the igc_rd32/wr32() MMIO accessors:

u32 igc_rd32(struct igc_hw *hw, u32 reg)

{

u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);

u32 value = 0;

if (IGC_REMOVED(hw_addr))

return ~value;

value = readl(&hw_addr[reg]);

/* reads should not return all F's */

if (!(~value) && (!reg || !(~readl(hw_addr))))

hw->hw_addr = NULL;

return value;

}

And:

#define wr32(reg, val) \

do { \

u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \

if (!IGC_REMOVED(hw_addr)) \

writel((val), &hw_addr[(reg)]); \

} while (0)

E.g. igb has similar checks in its MMIO accessors, and has a similar

macro E1000_REMOVED, which is implemented as follows:

#define E1000_REMOVED(h) unlikely(!(h))

These checks serve

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References